Care of Butterfly Bush - Knowledgebase Question

I live in zone 5 and am wondering about my butterfly bushes that I planted this year. Is there a special way to winter them? Also, in the spring do I trim them down so that they will start new branches or leave them alone. Do they grow from the old wood with no pruning in the sping? How long before I would know if they made it thru the winter..in other words when do they start leaving out in the spring? Thank-you for your time.

Butterfly bush is sometimes root hardy in zone 5. They have the best chance in a protected location that is sheltered from winter wind and where the soil is very well drained. To increase the chance of survival, mulch heavily in late fall after it stops growing for the season. In the spring, cut it down to about a foot tall. In late spring to early summer you should see new growth if it is still alive. It may come from the old wood or it may come from the roots or both. It blooms on new growth so this does not reduce flowering. Good luck!